McConnelsville is a village in and the county seat of Morgan County, Ohio, United States, on the east bank of the Muskingum River. Located 21 miles (34 km) southeast of Zanesville and 26 miles (42 km) northwest of Marietta, the population was 1,667 at the 2020 census.

Morgan County is a county located in the U.S. state of Ohio. As of the 2020 census, the population was 13,802, making it the third-least populous county in Ohio. Its county seat is McConnelsville. The county was created in 1817 and later organized in 1819. It is named for Daniel Morgan, an officer in the American Revolutionary War.